As multimedia communications have become more popular for mobile electronic devices, mobile electronic device users have increasingly desired reliable high data rate transmissions. Multi-user multiple input multiple output (MU-MIMO) can be used to meet the demand for higher data rates and better improved wireless coverage even without increasing average transmit power or frequency bandwidth because the MU-MIMO structure uses multiple spatial layers to deliver multiple data streams using a given frequency-time resource.
MU-MIMO is a radio communication technique using a transmitter and receivers that each have multiple antennas to wirelessly communicate with one another. Using multiple antennas at the transmitter and receivers allows the spatial dimension to be applied to improve the performance and throughput of a wireless link. MIMO communication can be performed in an open loop or closed loop technique. A transmitter using the open loop MIMO technique has minimal knowledge of the channel condition before signals are transmitted to a receiver. In contrast, closed loop MIMO can feed back channel-related information from the transmitter to the receiver to allow the transmitter to modify transmit signals before the signals are transmitted to better match channel state conditions. The amount of feed-back information that is delivered from a receiver to a transmitter in a system using closed loop MIMO can be very large. The ability to increase the transmission quality of the feedback channel in a closed loop MIMO system can be useful.